Method for reducing biofilm formation

ABSTRACT

A two phase method for reducing the formation of biofilm includes an evacuation of ambient air from a region about the surgical or treatment site, to extract airborne or aerosolized bacteria ejected from the site by the treatment. The extracted bacteria are prevented from settling back onto the cleansed tissue surface, thus at least reducing colonial bacteriological growth and concomitantly exuded biofilm material. A second phase involves the attachment of one or more ultrasonic transducers to the patient over or near a surgical treatment site after the surgery is terminated. Each applied ultrasonic transducer is used to vibrate the patient&#39;s tissues at the treatment site to disrupt biofilm formation.

BACKGROUND OF THE INVENTION

This invention relates to apparatus and method for reducing theformation of biofilm on a wound site particularly a wound site that hasbeen debrided to remove necrotic tissue.

Chronic wound infection represents a significant healthcare problemworldwide. Often the end objective of wound healing is the objective fornew therapeutic options. Yet chronic wounds compromise a number ofdifferent and complex conditions that each interferes with the healingprocess. For example, a chronic wound can comprise necrotic tissue inneed of debridement, bacterial infection in need of antimicrobial agentsand compromised vasculature that impedes the normal healing process.

One element of the chronic wound infection condition that impedeshealing is the formation of biofilm. Biofilm is the result of planktonicbacteria forming together and secreting exopolysaccharide (EPS) toadhere and protect the colonizing community. At the height of formation,EPS can make up between 75-90% of the total biofilm composition (Regt).Biofilm inhibits healing by creating an optimal condition for bacteriato grow, while simultaneously preventing antimicrobial agents fromdirect access to bacteria.

Methods to remove biofilm include ultrasonic debridement, topicalantimicrobials, suction, and surface cleansing. Each of these methodsalone treat an aspect of biofilm. For example, ultrasonic debridement ofwounds has proven to be the most effective mechanism in disrupting anddebulking a majority of the biofilm formation. Yet even in thispreferred method, biofilm debris can be left behind to propagate.Suction alone has not proven to be effective in removing biofilm, andcan potentially interfere with the operation of other methods likeultrasonic debridement if applied simultaneously.

U.S. Pat. No. 7,608,054 to Soring et al. describes a medical treatmentapparatus that combines an ultrasound sonotrode with a suction sheath.The fixed position between the tip of the suction and the tip of thesonotrode only allows for one simultaneous operation. In particular thisapproach is limited due to the potential interference of the suction tipduring the ultrasonic debridement operation.

U.S. Pat. No. 7,522,955 B2 to Rontal et al. describes a method andapparatus for ultrasonic cleaning of biofilm coated surfaces for sinuscavities within a human head. The method describes an ultrasonicapplication in combination with irrigation and suction that is designedto not remove any of the surrounding underlying tissue. This differssignificantly from an ultrasonic debridement of a wound bed, whichrequires the removal of tissue in combination with biofilm. Thus theultrasonic probe needs to operate in a a cavitation mode at the surfaceof a wound, causing expulsion of the biofilm.

Methods of mechanical removal of biofilm in wounds alone have proven tobe inadequate. What does not exist and what would be beneficial to themarket is a method to remove biofilm and prevent it from reforming inorder to allow wounds to heal.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide a method to inhibitbiofilm formation in order to allow wounds to heal more expeditiously.

A related object of the present invention is to provide a method forremoving biofilm so as to reduce the likelihood of the biofilmreforming.

Another related object of the present invention is to provide a methodto remove biofilm and prevent it from reforming in order to allow woundsto heal.

An associated object of the present invention is to provide apparatusfor removing biofilm with structure to assist in biofilm reformationreduction.

Another associated object of the present invention is to provideapparatus for inhibiting the formation of biofilm.

Although every feature of the invention is attained in at least oneembodiment of the invention, there is not necessarily any one embodimentthat achieves all of the objects of the invention.

SUMMARY OF THE INVENTION

The present invention broadly contemplates a method for the inhibitionof biofilm, a method for reducing the likelihood of biofilm formation.The method includes a surgical room cleansing process and a disruptionand removal. The method typically includes a mechanical debridement forthe removal of any existing necrotic tissue, surface infection orpreviously formed biofilm The mechanical debridement process results ina clean wound bed of healthy granulated tissue. Substantiallyimmediately following the mechanical debridement of a wound, anultrasound biofilm disrupter pad is placed on or near the wound toprevent bacterial adherence to the wound bed by excretion of EPS.

The ultrasound biofilm disrupter prevents adherence of bacteria to thewound by application of surface acoustic waves at a sufficient frequencyand amplitude to disrupt formation but below a threshold that stimulatesbacterial growth. In order to accomplish this, a wound-dressing device,which incorporates a disposable ultrasonic transducer, is applied to thewound site post debridement for duration sufficient to allow healing tooccur.

In a preferred embodiment ultrasound is used in the debridement processto mechanically remove necrotic tissue while cleansing the wound bed.The ultrasonic debridement should be in the 20 kHz frequency range inorder to simultaneously begin the process of biofilm disruption. Oncethe mechanical debridement is complete, a lower energy setting on thedebridement probe may be utilized to pre-condition the wound bed fordisrupting adherence or starting the formation of biofilm. Preferably,the wound bed is immediately covered with a wound dressing thatincorporates an ultrasonic biofilm disrupter transducer delivering asurface acoustic wave at 20 kHz with an acoustic power output of 0.2-0.4w/cm². The transducer is connected to a portable energy source. Theenergy source can be battery supplied. The wound dressing canincorporate an antimicrobial agent that is delivered during the biofilmdisruption treatment.

In another embodiment ultrasound is incorporated into the wound dressingand applied after standard wound cleansing protocols have beenadministered. These protocols can include saline wash, topicalantimicrobial agents applied. The combination of ultrasonic debridement,low-pulsed ultrasonic biofilm disruption and topical antimicrobialsproduces an important sequential approach to the management and removalof biofilm. The removal of biofilm results in the removal of animpediment to the wound healing process.

In another embodiment ultrasound is combined with suction to create anoptimal combination for disruption and removal of biofilm. One stage ofbiofilm is an excretion of seeding stage. So existing debridementprocesses can result in a bulking of the biofilm, but at the same time aseeding of the newly created wound bed. The seeding process can occurfrom a mechanical debridement alone. In this the process for biofilmdisruption is temporary at best. To correct this problem, ultrasonicdebridement is combined with a suction process that collects themechanically removed biofilm remnants or seeding agents.

In one embodiment of this combined ultrasound and suction approach, theultrasonic debridement probe is housed by a suction probe that operatesin two stages. The first stage is with the ultrasonic debridement probeengaged with the tissue and the suction tip surrounding the debridementtip so that it is in near contact to the tissue simultaneously to removethe mechanically disrupted biofilm. In the second stage of operation thesuction tip can be moved to a position that is not in contact or nearcontact with the tissue, but sufficient enough to capture any biofilmdebris that is propelled into the area.

In another embodiment the combination of ultrasound and suction may haveone or more stages of operation. The positioning of the suction tip inrelationship to the ultrasound tip can be configured for a variety ofdifferent combinations to cause better mechanical disruption and captureof that disrupted biofilm. The combination of both ultrasonic energy tocause debridement and suction to cause removal can be done in a varietyof different sequences. For example, ultrasonic mechanical debridementcan be performed on the majority of the wound bed prior to engagingsuction to capture any remnant amounts of biofilm on the wound bed. Inanother embodiment the ultrasonic mechanical debridement is performedsimultaneous to applying suction either at the tip or near the tip. Inanother embodiment the suction is incorporated into the ultrasonicdebridement probe to allow for a mechanical disruption and capture ofthe biofilm. In one embodiment the suction is at the periphery of theultrasonic debridement probe to allow for maximum capture of themechanically disrupted biofilm.

In another embodiment, the suction is interspersed throughout theultrasonic debridement probe so that any area of mechanical disruptionhas a corresponding area of capture capability.

In another embodiment, a disposable sheath incorporates a suctioncapability for capturing biofilm during an ultrasonic debridement. Inone embodiment the sheath has a multiple position for use during anultrasonic debridement. The sheath can capture both the debris that isexpelled during the debridement and any remaining debris at the surfaceof the wound bed. The sheath can then be disposed of to avoid risk ofcross contamination. The sheath may incorporate a sealing strategy tomaintain suction pressure while still allowing for multi positioning onthe suction tip in relationship to the ultrasonic debridement tip.

Accordingly, a medical therapeutic method pursuant to one aspect of thepresent invention utilizes an ultrasonic debridement instrument havingan operative tip and a suction channel. The method comprises (i)manipulating the instrument to place the operative tip against apatient's tissues at a preselected surgical site, (ii) during contact ofthe operative tip with the patient's tissues, generating an ultrasonicstanding wave in the instrument, thereby fragmenting necrotic tissue andundesired organic material at the surgical site, (iii) during thegenerating of the ultrasonic standing wave, disposing a suction inlet ata distal end of the suction channel proximate the surgical site and (iv)applying vacuum or negative pressure to the suction channel to removetissue debris fragmented organic material from the surgical site via thesuction inlet, (v) disposing a suction port at a position spaced fromthe surgical site, and (vi) during and/or after the generating of theultrasonic standing wave and the fragmenting of tissue and material,sucking ambient air from a region about the surgical site through thesuction port at the position.

Preferably, the suction port is provided on the ultrasonic debridementinstrument, and the method includes operating an actuator to enable thesucking of air through the suction port.

In one embodiment of the instrument, the actuator may include a sheathor sleeve which is slidably mounted to the instrument for longitudinalmotion alternately in opposing directions along the shaft or probeportion thereof. The operating of the actuator then includes shiftingthe sheath or sleeve in a proximal direction along the instrument. Wherethe instrument includes a longitudinally shiftable sheath or sleeve,with the suction channel being located between the sheath or sleeve anda shaft or horn of the instrument, the suction inlet and the suctionport may both be defined by the distal end of the sheath or sleeve, theposition of the sleeve determining whether an intake opening is locatedat the operative tip of the instrument, and is thus the suction inlet,or is spaced from the operative tip and is therefore the suction port.Accordingly, the method may further comprise shifting the sheath orsleeve in a proximal direction after the applying of a vacuum ornegative pressure and prior to the sucking of the ambient air throughthe suction port, a distal tip of the sheath or sleeve defining thesuction inlet in a distal position of the sheath or sleeve, the distaltip defining the suction port in a proximal position of the sheath orsleeve.

In one or more alternative embodiments the suction inlet and the suctionport may be different and always mutually spaced from one another. Ifthe instrument includes a slidable sheath or sleeve, the position ofthat element may determine whether the suction inlet and/or the suctionport is active. Thus, the sheath or sleeve may include valves foropening and closing air pathways extending to the suction inlet and thesuction port, in dependence on the longitudinal position of the sheathor sleeve. Alternatively, valves may be operated separately viarespective electromechanical actuators so that the opening and closingof the suction inlet is controllable independently of the opening andclosing of the suction port.

Thus, where the suction port is different from the suction inlet, thesuction port being located proximally along the instrument from thesuction input, the operating of the actuator may include directingsuction under-pressure to the suction port. The actuation may includeoperating a valve to open a suction pathway to the suction port.

In accordance with another feature of the invention, the method mayalternatively or additionally comprise placing an ultrasonic transduceron the patient at least proximate the surgical site after terminating ofa debridement process and while the surgical site is free of discerniblebacteria. Typically, the transducer is placed immediately after thesurgical site has been cleaned of necrotic tissue and other undesirabledebris and even prior to the removal of the patient from the operatingroom. After the placing of the transducer and while the transducer is ineffective vibration-transmitting contact with the patient, an electricalenergization waveform of an ultrasonic frequency is conducted to thetransducer at least intermittently during a period of approximately oneday or longer to prevent biofilm formation on the patient at thesurgical site and facilitate a healing of the patient's tissue at thesurgical site.

The transducer may be affixed to a carrier pad, the placing of thetransducer on the patient including attaching the pad to the patient.Alternatively, the transducer may be disposed in a balloon or bladderinflated with a gel or other medium conducive to the effectivetransmission of ultrasonic pressure waves, the balloon or bladder beingattached to the patient over or adjacent the surgical site. Othertransducer carriers and methods of attachment to the patient will occurto those skilled in the art.

Accordingly, a medical therapeutic method comprises (a) removingnecrotic tissue and undesired organic material from a surgical site on apatient, (b) shortly thereafter, while the surgical site is free ofdiscernible bacteria, placing at least one ultrasonic transducer on thepatient at least proximate the surgical site, and (c) after the placingof the transducer and while the transducer is in effectivevibration-transmitting contact with the patient, conducting anelectrical energization waveform of an ultrasonic frequency to thetransducer at least intermittently during a period of approximately oneday or longer, the waveform having frequency, amplitude and duration toeffectively reduce formation on the patient at the surgical site andthereby facilitate a healing of the patient's tissue at the surgicalsite. The placing of the transducer preferably includes removablyattaching the transducer to the patient atop tissues at the surgicalsite.

A surgical device comprises an ultrasonic probe having an operative tip,an electromechanical transducer operatively connected to the probe forgenerating an ultrasonic standing wave in the probe, and at least onesheath or sleeve disposed about the probe and defining at least a firstsuction port at a distal end of the probe, proximate the operative tip,and a second suction port spaced from the distal end of the probe.

The one or more sheaths or sleeves may take the form of exactly onesheath or sleeve slidably attached to the probe to shift between adistal position and a proximal position, wherein a distal end of thesheath or sleeve is alternately locatable (i) proximate the operativetip to define the first suction port and (ii) at a predetermineddistance from the operative tip to define the second suction port.

Alternatively, the first suction port and the second suction port aredifferent openings in the at least one sheath or sleeve. Theiroperational status may be separately controlled via respective valves.Moreover, the suction ports may be connectable to vacuum sources ofdifferent strengths. The magnitude of the vacuum or negative pressureapplied to the proximal port is typically greater than the magnitude ofthe vacuum or negative pressure applied to the distal port.

The sheath or sleeve may define a first suction channel extending to thefirst suction port and a separate second suction channel extending tothe second suction port, the first suction channel and the secondsuction channel being subjectable to different negative pressures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is partially a schematic cross-sectional view and partially ablock diagram of a system for removing biofilm from a wound site andreducing the likelihood of biofilm reformation thereafter.

FIG. 2 is partially a schematic cross-sectional view and partially ablock diagram of another apparatus for removing biofilm from a woundsite and reducing the likelihood of biofilm reformation thereafter.

FIG. 3 is partially a schematic cross-sectional view and partially ablock diagram of yet a further apparatus for removing biofilm from awound site and reducing the likelihood of biofilm reformationthereafter.

FIG. 4 is partially a schematic cross-sectional view and partially ablock diagram of a device for attachment to a patient at a wound site,to reduce the likelihood of biofilm formation on the wound site.

FIG. 5 is a schematic top plan view and partially a block diagram of thedevice of FIG. 4, in position and attached to a patient at a wound siteon the patient.

FIG. 6 is a schematic perspective view of another device for attachmentto a patient at a wound site, to reduce the likelihood of biofilmformation.

FIG. 7 is partially a schematic cross-sectional view and partially ablock diagram of a device for attachment to a patient at a wound site,to reduce the likelihood of biofilm formation on the wound site, showingattachment of the device to a patient's limb.

DETAILED DESCRIPTION

The present disclosure contemplates a two phase method for reducing theformation of biofilm. The first phase is performed where a wound site isbeing treated for removal of necrotic tissue, eschar or biofilm andincludes an evacuation of ambient air from a region about the surgicalor treatment site, to extract airborne or aerosolized bacteria ejectedfrom the site by the treatment. The extracted bacteria are preventedfrom settling back onto the cleansed tissue surface, thus at leastreducing colonial bacteriological growth and concomitantly exudedbiofilm material. The second phase or approach for reducing biofilminvolves the attachment of one or more ultrasonic transducers to thepatient over or near a surgical treatment site after the surgery isterminated. Each applied ultrasonic transducer is used to vibrate thepatient's tissues at the treatment site to disrupt biofilm formation.The two phases of treatment may be used separately depending on theapplication. Thus, ultrasonic biofilm disruption may be used at woundsites which have not been subjected to formal processes for removal ofnecrotic tissue, eschar or biofilm.

Accordingly, a medical therapeutic method may utilize an ultrasonicdebridement instrument 10 (FIG. 1) having an operative tip or surface 12and a suction channel 14 defined between an outer surface 16 of anultrasonic horn 18 and an inner surface 20 of a cannula or sheath 22.The method comprises manipulating the instrument 10 to place theoperative tip or surface 12 against a patient's tissues PT at apreselected surgical site SS. During contact of the operative tip 12with the patient's tissues PT, one operates a waveform generator 23 togenerate an ultrasonic standing wave in the instrument 10 andparticularly in probe or horn 18, to thereby fragment necrotic tissueand undesired organic material at the surgical site SS. During thegenerating of the ultrasonic standing wave, a suction inlet 24 at adistal end of the suction channel 14 is disposed proximate the surgicalsite SS and a vacuum or negative pressure is applied to the suctionchannel 14 to suck tissue debris and fragmented organic material fromthe surgical site SS via the suction inlet 24. A suction port 26 ofanother instrument 28 is disposed at a position spaced at a distance D1from the surgical site SS. During and/or after the generating of theultrasonic standing wave and the fragmenting of tissue and material byinstrument 10, instrument 28 is operated to suck ambient air, asindicated by arrows 30, from a region R about the surgical site SSthrough suction port 26. While suction inlet 24 is typically locatedbetween 1 and 5 mm from the surgical site SS and the tissue surface atthe surgical site, suction port 26 is typically located 2-6 cm from thetissue surface at the surgical site SS.

As depicted in FIG. 1, instrument 28 may be formed at a distal end withan enlarged or expanded extension 32, such as a cone, to funnel air 30into the instrument. A suction source or vacuum generator 34communicating with a lumen 36 of instrument 28 may exert a greatersuction force than that of a suction source or vacuum generator 38communicating with suction channel 14.

In an alternative approach, instrument 28 is omitted. Instead, cannulaor sheath 22 is shiftably mounted to probe or horn 18 for longitudinalmotion alternately in opposing directions along the shaft or probeportion thereof, thereby enabling the user to position the suction port,defined in part by the distal edge of the sheath, in two or morealternative locations, a most distal location adjacent the operative tip18 of the probe or horn 12 and a more proximal location. As indicated bya double headed arrow 40, cannula or sheath 22 is pulled in a proximaldirection after an operation removing tissue or other organic matterfrom surgical site SS so that suction port 26 is located at a distance dfrom the operative tip or surface 12 of instrument 10. An actuator suchas suction source 38, or a switch component thereof, is operated toenable the sucking of air through suction port 26 at the retractedposition of cannula or sheath 22. In a simple configuration, suctionsource 38 may have two operating states, on and off, the position ofsheath 22 determining whether suction is applied at the surgical site SSor at a distance therefrom. In a slightly more complicatedconfiguration, suction source 38 may be provided with three operatingstates, namely, off, high suction and low suction. The degree of suctionmay be selectable by the operator or may be automatically controlled inaccordance with the longitudinal or axial position of sheath 22 alongprobe or horn 12. For instance, sheath or sleeve 22 may be provided withvalves (not shown) for opening and closing air pathways in dependence onthe longitudinal position.

An alternative instrument assembly 50 depicted in FIG. 2 has anoperative tip or surface 52 and a suction channel 54 located between anouter surface 56 of an ultrasonic horn 58 and an inner surface 60 of afirst or inner sheath 62. A second, outer, sheath 64 surrounds the firstsheath 62 and defines therewith a second suction channel 66 for theevacuation of ambient air from a sizable region R′ about the surgicalsite SS, exemplarily through a conical port element 68 at the distal endof the outer sheath 64. The two suction channels 54 and 66 may beconnected to respective suction sources or vacuum generators 70 and 72via respective valves 74 and 76 both actuatable by the operator via acontrol unit 78. Control unit 78 is tied to a control input (notseparately designated) of an ultrasonic waveform generator 80 that isoperatively connected to probe or horn 12 via an electromechanicaltransducer (not shown) such as a stack of piezoelectric crystals.Control unit 78 may be programmed to open valve 76 within a selectabletime interval after the opening of valve 74 and the activation ofwaveform generator 80.

In a surgical procedure, instrument assembly 50 is manipulated to placethe operative tip or surface 52 against patient's tissues PT′ at apreselected surgical site SS′. During contact of the operative tip 52with the patient's tissues PT′, control unit 78 is operated to activatewaveform generator 80, which generates an ultrasonic standing wave inprobe or horn 58, to thereby fragment necrotic tissue and undesiredorganic material at the surgical site SS′. During the generating of theultrasonic standing wave, a suction inlet 82 at a distal end of innersuction channel 54 is disposed proximate the surgical site SS′ and avacuum or negative pressure is applied by suction source 70 to thesuction channel 54 via valve 74 to suck tissue debris and fragmentedorganic material from the surgical site SS′ through the suction inlet82. Conical port element 68 is disposed at a distance D2 from thesurgical site SS′. During and/or after the generating of the ultrasonicstanding wave and the fragmenting of tissue and material by instrument50, vacuum generator 72 and valve 76 are actuated by control unit 78 tosuck ambient air, as indicated by arrows 84, from region R′ throughsuction port or cone 68. Suction inlet 82 is typically located a minimaldistance, exemplarily between about 1 and about 5 mm, from tissues atthe surgical site SS′ while suction port 68 distance D2 is typically 2-6cm from the surgical site SS′.

Outer sheath 64 may be temporarily fixed to inner sheath 62 via aquick-release lock 86 such as a set screw. Thus, the relative axialpositions of sheaths 62 and 64 may be adjusted to change distance D2.Control unit 78 may be connected to suction sources or vacuum generators70 and 72 for varying the power usage thereof and average magnitudes ofthe negative pressures generated thereby.

FIG. 3 illustrates a modification 90 of the instrument assembly 50 ofFIG. 2. Instead of outer sheath 64, a suction nozzle 92 is attached tosheath 62. Nozzle 92 is connected to suction source or vacuum generator72 via a reinforced hose 94. Nozzle 92 is removably secured to sheath 62via a locking element 96 such as a ring clamp or a set screw. Theoperation of modified instrument 90 is as discussed above.

The present method alternatively or additionally comprises placing anultrasonic transducer 102 (see, e.g., FIGS. 4 and 5) in effectivecontact with a patient TP at least proximate a surgical site SI afterterminating of a debridement or other tissue cleaning procedure andwhile the surgical site SI is free of discernible bacteria. Typically,transducer 102 is placed immediately after the surgical site SI has beencleaned of necrotic tissue and other undesirable debris and even priorto the removal of the patient TP from the operating room. After theplacing of transducer 102 and while the transducer is in effectivevibration-transmitting contact with the patient TP, an electricalenergization waveform of an ultrasonic frequency is conducted from awaveform generator 104 to transducer 102 at least intermittently duringa period of approximately one day or longer to reduce, if not prevent,biofilm formation on the patient at the surgical site SI and therebyfacilitate a healing of the patient's tissue at the surgical site.

As depicted in FIG. 4, transducer 102 may be affixed to a carrier pad106, exemplarily sandwiched between layers 108 of a biocompatible andultrasound transmitting material. The placing of transducer 102 on thepatient TP preferably includes attaching pad 106 to the patient, forexample, via an adhesive layer 110. As depicted in FIG. 5, pad 106 isdisposed alone or together with one or more other carrier pads 106′, ona tissue surface TS proximate surgical site SI. Alternatively, pad 106may be placed directly over the surgical site SI shortly, if notimmediately, after tissue removal is complete. In that case adhesivelayer 110 may be omitted in favor of a layer of gel. The gel may beoxygenated and contain antibiotics. As depicted in FIG. 6, straps orbands 112 may be provided for securing the pad 106 to the patient TP.

Alternatively, as depicted in FIG. 7, an electromechanical,specifically, a piezoelectric, transducer 114 may be disposed inside aballoon or bladder 116 inflated with a gel or other medium 118 conduciveto the effective transmission of ultrasonic pressure waves, the balloonor bladder being attached to a patient TP′ over or adjacent a surgicalsite SI′. Balloon or bladder 116 is affixed to a patient, e.g., aroundan arm or leg PL, over or near a surgical site ST and an ultrasonicwaveform generator 120 is activated to generate ultrasonic vibrationsconducted into the patient's tissue to disrupt biofilm formation. Othertransducer carriers and methods of attachment to the patient will occurto those skilled in the art.

A medical therapeutic method utilizing one or more of the transducerdevices shown in FIGS. 4-7, first comprises cleaning surgical site SI orST of necrotic tissue and undesired organic material, for instance viaultrasonic debridement and suction as discussed above with reference toFIGS. 1-3. Shortly thereafter, while the surgical site SI or ST is freeof discernible bacteria, one places at least one ultrasonic transducer102, 114 on the patient TP, TP′ proximate or on the surgical site SI,ST, and thereafter, while the transducer is in effectivevibration-transmitting contact with the patient TP, TP′, conducting anelectrical energization waveform of an ultrasonic frequency to thetransducer 102, 114 at least intermittently during a period ofapproximately one day or longer. The waveform has frequency, amplitudeand duration parameters selected to effectively reduce biofilm formationon the patient TP, TP′ at the surgical site SI, ST and therebyfacilitate a healing of the patient's tissue at the surgical site. Theultrasound generates a surface acoustic wave at 20 kHz with an acousticpower output of 0.2-0.4 w/cm². The treatment period is long enough toenable healthy tissue formation. The placing of the transducer 102, 114preferably includes removably attaching the transducer to the patientatop tissues at the surgical site SI, ST.

What is claimed is:
 1. A medical therapeutic method comprising:providing an ultrasonic debridement instrument having an operative tipand a suction channel; manipulating said instrument to place saidoperative tip against a patient's tissues at a preselected surgicalsite; during contact of said operative tip with the patient's tissues,generating an ultrasonic standing wave in said instrument, therebyfragmenting necrotic tissue and undesired organic material at saidsurgical site; during the generating of said ultrasonic standing wave,disposing a suction inlet at a distal end of said suction channelproximate the surgical site; during the generating of said ultrasonicstanding wave, applying vacuum or negative pressure to said suctionchannel to remove tissue debris fragmented organic material from saidsurgical site via said suction inlet; disposing a suction port at aposition spaced from said surgical site; and during and/or after thegenerating of said ultrasonic standing wave and the fragmenting oftissue and material, sucking ambient air from a region about saidsurgical site through said suction port at said position.
 2. The methoddefined in claim 1 wherein said suction port is on said instrument,further comprising operating an actuator to enable the sucking of airthrough said suction port.
 3. The method defined in claim 2 wherein theoperating of said actuator includes shifting a sheath or sleeve in aproximal direction along said instrument.
 4. The method defined in claim2 wherein said suction port is different from said suction inlet, saidsuction port being located proximally along said instrument from saidsuction input, the operating of said actuator including directingsuction under-pressure to said suction port.
 5. The method defined inclaim 2 wherein said instrument includes a longitudinally shiftablesheath or sleeve, said suction channel being located between said sheathor sleeve and a shaft or horn of said instrument, further comprisingshifting said sheath or sleeve in a proximal direction after theapplying of a vacuum or negative pressure and prior to the sucking ofthe ambient air through said suction port, a distal tip of said sheathor sleeve defining said suction inlet in a distal position of saidsheath or sleeve, said distal tip defining said suction port in aproximal position of said sheath or sleeve.
 6. The method defined inclaim 1, further comprising: placing at least one ultrasonic transduceron the patient at least proximate the surgical site after terminating ofa debridement process and while the surgical site is free of discerniblebacteria; and after the placing of said transducer and while saidtransducer is in effective vibration-transmitting contact with thepatient, conducting an electrical energization waveform of an ultrasonicfrequency to said transducer at least intermittently during a period ofapproximately one day or longer to at least reduce biofilm formation onthe patient at the surgical site and facilitate a healing of thepatient's tissue at the surgical site.
 7. The method defined in claim 6wherein said transducer is affixed to a carrier pad, the placing of saidtransducer on the patient including attaching said pad to the patient.8. The method defined in claim 6, further comprising utilizing saidinstrument at a lower energy setting to pre-condition the tissues at thesurgical site for disrupting adherence or starting the formation ofbiofilm.
 9. A medical therapeutic method comprising: removing necrotictissue and undesired organic material from a surgical site on a patient;after the removal of all discernible necrotic tissue and undesirableorganic material from the surgical site and while the surgical site isfree of discernible bacteria, placing at least one ultrasonic transduceron the patient at least proximate the surgical site; and after theplacing of said transducer and while said transducer is in effectivevibration-transmitting contact with the patient, conducting anelectrical energization waveform of an ultrasonic frequency to saidtransducer at least intermittently during a period of approximately oneday or longer, said waveform having frequency, amplitude and duration toeffectively reduce biofilm formation on the patient at the surgical siteand thereby facilitate a healing of the patient's tissue at the surgicalsite.
 10. The method defined in claim 9 wherein the placing of saidtransducer includes removably attaching said transducer to the patient.11. The method defined in claim 10 wherein the placing of saidtransducer includes removably attaching said transducer atop tissues atthe surgical site.
 12. The method defined in claim 10 wherein saidtransducer is affixed to a carrier pad, the placing of said transduceron the patient including attaching said pad to the patient.
 13. Themethod defined in claim 9 wherein the removing of necrotic tissuesincludes operating an ultrasonic debrider instrument at a first energysetting, further comprising utilizing said instrument at a lower secondenergy setting to pre-condition the tissues at the surgical site fordisrupting adherence or starting the formation of biofilm.
 14. Asurgical device comprising: an ultrasonic probe having an operative tip;an electromechanical transducer operatively connected to said probe forgenerating an ultrasonic standing wave in said probe; and at least onesheath or sleeve disposed about said probe and defining at least a firstsuction port at a distal end of said probe, proximate said operativetip, and a second suction port spaced from said distal end of saidprobe.
 15. The surgical device defined in claim 14 wherein said at leastone sheath or sleeve is exactly one sheath or sleeve slidably attachedto said probe to shift between a distal position and a proximalposition, wherein a distal end of said sheath or sleeve is alternatelylocatable (i) proximate said operative tip to define said first suctionport and (ii) at a predetermined distance from said operative tip todefine said second suction port.
 16. The surgical device defined inclaim 14 wherein said first suction port and said second suction portare different openings in said at least one sheath or sleeve.
 17. Thesurgical device defined in claim 16 wherein said at least one sheath orsleeve defines a first suction channel extending to said first suctionport and a separate second suction channel extending to said secondsuction port, said first suction channel and said second suction channelbeing subjectable to different negative pressures.